In an effort to deal with an increasing number of immigrants, in 1892 the U.S. government either banned or put limitations on many potential immigrants coming from Europe and Asia, especially China.
Enslaved Africans resisted, or rebelled, against their position as slaves in many different ways. Each expression of resistance by enslaved individuals or groups counted as acts of rebellion against the system of slavery. The many instances of resistance show that slaves were not passive victims of slavery. Instead they proved their strength and determination in fighting for their freedom. In particular, enslaved Africans on the Caribbean plantations rebelled against their owners in many different ways.
Link to: This can be read about further in Black Resistance.
Answer: The purpose is to measure the overall cost of goods and services that would be brought in by a consumer.